Effectively Managing Source Water Quality Affecting Downstream Recycled Water Treatment Plants

Improving secondary effluent water quality can lead to more efficient operations and higher product water quality at downstream water recycling facilities. The East Bay Municipal Utility District (EBMUD) in Oakland, California, utilizes secondary effluent from a nearby agency as source water for its two largest recycled water projects—the North Richmond Water Reclamation Plant (NRWRP) and the Richmond Advanced Recycled Expansion (RARE) facility. In order to improve final product water quality and operations at these two facilities, EBMUD conducted a targeted water quality study to identify process and operational parameters related to secondary effluent quality. In particular, the study focused on process parameters that could be contributing to spikes in secondary effluent ammonia. Analysis showed that low effluent pH and low aeration basin dissolved oxygen (DO) levels were correlated with spikes in secondary effluent ammonia. Key recommendations include chemical addition to buffer pH and improved oxygen feed distribution.